XML Schema 参考手册 完整 XML Schema 参考手册 The sequence element requires the elements in the group to appear in the containing elements in the specified order. Each child element can appear 0 to any number of times. 父元素： Group, choice, sequence, complexType, restriction (both simpleContent and complexContent), extension (both simpleContent and complexContent) (? Declares that the element can appear zero or once in the sequence element. ) Attribute Description Id Optional. Specifies the unique ID of the element. MaxOccurs Optional. Specifies the maximum number of times an any element can appear in the parent element. The value can be an integer greater than or equal to zero. If you do not want to set any limit on the maximum number of times, use the string “unbounded”. The default value is 1. MinOccurs Optional. Specifies the minimum number of times an any element can appear in the parent element. The value can be an integer greater than or equal to zero. To specify that the any group is optional, set this property to zero. The default value is 1. Any attributes Optional. Specifies any other attributes with the non-schema namespace. This example is a declaration for the “personinfo” element, which must contain the following five elements in order: “firstname”, “lastname”, “address”, “city”, and and “country”. This example is a declaration for the “pets” element, which can contain zero or more dog and cat elements: XML Schema 参考手册 完整 XML Schema 参考手册
In recent years, Geographic Information Systems (GIS) have undergone rapid development in both theoretical and practical dimensions. GIS has been widely applied for modeling and decision-making support across various fields such as urban management, regional planning, and environmental remediation, establishing geographic information as a vital component of the information era. The introduction of the “Digital Earth” concept has further accelerated the advancement of GIS, which serves as its technical foundation. Concurrently, scholars have been dedicated to theoretical research in areas like spatial cognition, spatial data uncertainty, and the formalization of spatial relationships. This reflects the dual nature of GIS as both an applied technology and an academic discipline, with the two aspects forming a mutually reinforcing cycle of progress. Definition and usage ¶
Element information ¶
Grammar ¶
Example 1 ¶
<xs:element name="personinfo">
<xs:complexType>
<xs:sequence>
<xs:element name="firstname" type="xs:string"/>
<xs:element name="lastname" type="xs:string"/>
<xs:element name="address" type="xs:string"/>
<xs:element name="city" type="xs:string"/>
<xs:element name="country" type="xs:string"/>
xs:sequence>
xs:complexType>
xs:element>
Example 2 ¶
<xs:element name="pets">
<xs:complexType>
<xs:sequence minOccurs="0" maxOccurs="unbounded">
<xs:element name="dog" type="xs:string"/>
<xs:element name="cat" type="xs:string"/>
xs:sequence>
xs:complexType>
xs:element>
Principles, Technologies, and Methods of Geographic Information Systems
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